Civil commitment of the mentally ill continues to pose a major dilemma for the mental health system and communities throughout the nation. While it is recognized that commitment is necessary in some cases, there is widespread concern that the evaluation process is inconsistently applied and thus arbitrary in nature. This study will attempts to show that emergency assessments are or can be made reliably and with face validity, that admission decisions can be made relatively impervious to extraneous considerations, and that professional standards used in the assessments can be clearly stated and their application clearly described. The objective of this study is completion of three indexes which validly reflect how psychiatric emergency room admission personnel use statutory guidelines of dangerousness and grave disability due to mental disorder in the involuntary hospitalization of the mentally ill. Based on a review of standard practice texts, research efforts, legal guidelines in the California Welfare and Institutions Code, and observations of admission procedures in psychiatric emergency rooms, we will develop l) an index of the extent to which a patient can be perceived as dangerous and/or gravely disabled (this index will be composed of an inclusive set of indicators of these statuses scaled according to severity), 2) A measure of the evidentiary quality of the information which comprises the indicators of dangerousness and grave disability index; and 3) A measure of psychiatric symptomology to capture the mental disorder component of the assessment. Observations of 375 assessments of dangerousness and grave disability due to mental disorder will be completed in five psychiatric emergency rooms leading to the development of these indexes. Assessment of the reliability and validity of the indexes will respectively determine how consistently mental health professionals can use the measures and how well the measures reflects the clinical and evidentiary assessment processes carried out by clinicians in the emergency room. Finally, factors will be identified that are most significant in determining how dangerous and/or gravely disabled a person is perceived to be, and whether or not an individual is involuntarily admitted to a hospital .